One of the most demanding applications for crushed stone is as railroad ballast. Ballast is usually produced from natural deposits of granite, trap rock, quartzite, dolomite or limestone. Ballast serves as a bed for railroad tracks and provides track stability, drainage, and support of significant loads carried by railcars. In addition, it deters the growth of vegetation and allows for track maintenance to be performed more easily.
Near a railroad crossing, a transmitter and receiver associated with a crossing warning system apply and detect electrical signals across the tracks. These elements are used to determine when to activate a crossing protection system. A crossing protection system includes, but is not limited to, such parts as gates, bells, lights, etc.
Over time, due to environmental conditions and debris, ballast may deteriorate. Deteriorated ballast can cause instability in the railroad track. Additionally, it is possible that the deterioration may result in the ballast becoming conductive. If the deterioration results in the ballast becoming more conductive, it is possible that a crossing warning system may falsely activate a crossing protection system when a train is not approaching a road crossing. It should be noted that false activations tend to “de-sensitize” the general public to the protection provided by the crossing warning system, such that they may ignore it.